Hannover 2020 – scientific programme

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P: Fachverband Plasmaphysik

P 10: Poster Session 2

P 10.27: Poster

Tuesday, March 10, 2020, 16:30–18:30, Empore Lichthof

Spoke-synchronised optical emission spectroscopy in a high-power impulse magnetron discharge — •Philipp Maaß, Julian Held, Volker Schulz-von der Gathen, and Achim von Keudell — Experimental Physics 2, Ruhr-University Bochum, Germany

High-power impulse magnetron sputtering (HiPIMS) is a physical vapour deposition technique in which a plasma is ignited in front of a target in order to sputter atoms from the target and coat a substrate. In such a plasma, inhomogeneities, which appear as localised light emissions - so-called spokes -, can be detected. They move in ExB-direction at a velocity of about 10 km/s.

Spokes appear in the magnetic trap region in front of the magnetron. In order to further investigate them, non-intrusive measurements are needed. Optical emission spectroscopy seems the best option, is however limited due to the stochasticity of the spokes' appearance in space and time. Therefore, a triggering system was developed that enables the recording and investigation of spoke-synchronised measurements.

The triggered OES measurements were performed using a CCD-camera and filters in a frontal and an orthogonal set-up aimed at the target. The spokes were found to have very complex internal structures indicated by the sequence of filtered emissions. The spread of the spokes was discovered to be large, extending to the last closed magnetic field line.